This invention relates to a method for terminating solid electrolyte capacitors, and more particularly to such methods that include mounting metal terminal cups to opposite ends of solid electrolyte capacitors.
Such methods are known whereby rectangular metal cups are individually placed over the ends of a rectangular solid electrolyte capacitor body with a liquid bonding material therebetween. Several difficulties are inherent in these known methods.
There is usually a substantial variation in the outer dimensions of the capacitor bodies that is a result of the numerous conformal layers and coatings having been applied to a porous valve metal pellet to form the capacitor body. These layers are generally applied by dipping, spraying or other liquid application steps and the overall dimensions are the sum of many broad thickness tolerance layers. Thus the cups to be bonded thereto do not fit well and are particularly subject to twisting and misalignment with the rectangular pellet. As a result, when the two cups have been assembled to opposite ends of a capacitor body they are not aligned with each other. The user subsequently experiences difficulty in the stable placement of the capacitor on the conductors of a printed circuit board to which they are to be soldered or otherwise connected, and the quality of the connections is adversely affected. The smaller the capacitor body is, the greater this termination misalignment tends to become.
Furthermore the individual positioning of the cups on the body by manual means is arduous and time consuming, the operator typically performing this task with tweezers and with the aid of optical magnification.
It is therefore an object of this invention to overcome the above mentioned drawbacks of known methods.
It is a further object of this invention to provide a solid electrolyte capacitor with metal cup terminations having near perfect alignment between cups.
It is a further object of this invention to provide a reduced cost batch method for making solid electrolyte capacitors with metal cup terminations.